1. Field of the Invention
The present invention relates to a rotary electromagnetic actuator for rotating a first operating member and a second operating member in association with each other through an electromagnetic driving source.
2. Description of Related Art
FIGS. 11A and 11B show a prior art electromagnetic actuator A used in a shift lock device for limiting the movement of a select lever for an automatic transmission of an automobile.
The electromagnetic actuator A includes an on-off solenoid 2 for driving a plunger 1 in advancing and retracting movements by an electromagnetic force, a first link 4 rotatably supported on a first stationary shaft 3 fixed to a housing, and a second link 6 rotatably supported on a second stationary shaft 5 fixed to the housing. A pin 41 provided on the first link 4 is engaged in an elongated bore 11 defined at a tip end of the plunger 1, and a pin 61 provided on the second link 6 is engaged in an elongated bore 42 defined in the first link 4.
Therefore, when the on-off solenoid 2 is in its non-excited state in which the plunger 1 has been advanced, as shown in FIG. 11A, the first link 4 having the pin 41 pushed in the elongated bore 11 in the plunger 1 is rotated clockwise about the first stationary shaft 3, and in association with this rotation, the second link 6 having the pin 61 pushed in the elongated bore 42 in the first link 4 is rotated counterclockwise about the second stationary shaft 5. As a result, locking surfaces 7 and 8 provided at tip ends of the first and second links 4 and 6 are moved toward each other, whereby the locking surface 7 of the first link 4 blocks a path of movement of a locked member 9 of a select lever from a neutral range, or the locking surface 8 of the second link 6 blocks a path of movement of the locked member 9 of the select lever from a parking range, thereby inhibiting the operation of the select lever.
When the on-off solenoid 2 is brought into its excited state to retract the plunger 1, as shown in FIG. 11B, the first link 4 having the pin 41 pulled in the elongated bore 11 in the plunger 1 is rotated counterclockwise about the first stationary shaft 3, and in association with this rotation, the second link 6 having the pin 61 pulled in the elongated bore 42 in the first link 4 is rotated clockwise about the second stationary shaft 5. As a result, the locking surfaces 7 and 8 provided at tip ends of the first and second links 4 and 6, respectively, are moved away from each other, whereby the locking surface 7 of the first link 4 and the locking surface 8 of the second link 6 are retracted from the path of movement of the locked member 9 of the select lever, thereby permitting the operation of the select lever.
The above-described prior art electromagnetic actuator A suffers from the following problem: The plunger 1 and the first link 4 are engaged with each other by the elongated bore 11 and the pin 41, and the first link 4 and the second link 6 are engaged with each other by the elongated bore 42 and the pin 61. For this reason, not only the number of parts and the number of assembling steps are increased, but also looseness is produced in the engaged portions, whereby a smooth operation is obstructed.
Moreover, the prior art electromagnetic actuator A suffers from another problem. That is, it has slide areas at four points (1), (2), (3) and (4) which will be described below, and for this reason, the sliding resistance is increased and the burden of the on-off solenoid 2 is increased:
(1) a slide area between the elongated bore 11 of the plunger 1 and the pin 41 of the first link 4;
(2) a slide area between the first stationary shaft 3 and the first link 4;
(3) a slide area between the elongated bore 42 in the first link 4 and the pin 61 of the second link 6; and
(4) a slide area between the second stationary shaft 5 and the second link 6.
To reduce the sliding resistance, it is necessary to apply a lubricant such as silicone grease to each of the slide areas. However, this is accompanied by the following problem: The viscosity of the lubricant increases with the dropping of the temperature. For this reason, if the size of the on-off solenoid 2 is increased in order to overcome the sliding resistance even at a very low temperature to ensure a smooth operation, the driving force of the on-off solenoid becomes excessive at ambient temperature at which the viscosity of the lubricant decreases to make the sliding resistance decreased. This causes the plunger 1 to strike strong a stopper at the end of its stroke, thereby making a noise. Especially, the on-off solenoid 2 has such a characteristic that the driving force is changed largely relative to the stroke of the plunger 1. For this reason, when the driving force of the on-off solenoid 2 is increased in the vicinity of the end of the stroke, there is a possibility that the noise may grow further larger.
Accordingly, it is an object of the present invention to provide a rotary electromagnetic actuator for rotating a first operating member and a second operating member in association with each other through an electromagnetic driving source, wherein the structure of the rotary electromagnetic actuator is simplified, leading to reductions in number of parts and number of assembling steps.
It is another object of the present invention to provide a rotary electromagnetic actuator for rotating a first operating member and a second operating member in association with each other through an electromagnetic driving source, wherein the application of a lubricant is not required, and the noise is reduced.
It is a further object of the present invention to provide a rotary electromagnetic actuator for rotating a first operating member and a second operating member in association with each other through an electromagnetic driving source, wherein the driving force is prevented from being changed largely even in the vicinity of the end of the stroke to reduce the noise.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a rotary electromagnetic actuator comprising an electromagnetic driving source including a driving rotary shaft rotatably carried in a housing and driven in rotation by an electromagnetic force, a follower rotary shaft rotatably carried in the housing, a first operating member carried on and rotated in unison with the driving rotary shaft, a second operating member carried on and rotated in unison with the follower rotary shaft, and an operatively connecting means for permitting the first operating member and the second operating member to be rotated in association with each other.
With the above arrangement, when the electromagnetic driving source is driven to rotate the driving rotary shaft, the first operating member is rotated in unison with the driving rotary shaft. This rotation of the first operating member is transmitted through the operatively connecting means to the second operating member to rotate the second operating member in unison with the follower rotary shaft. Therefore, the first and second operating members can be rotated in unison with each other. In addition, it is unnecessary to provide a pin and an elongated bore, or means for converting a rectilinear motion to a rotational motion such as a stationary shaft and a link in a path of transmitting the driving force from the electromagnetic driving source to the first and second operating members. Therefore, not only the number of parts and the number of assembling steps are reduced, but also the number of slide areas where a friction resistance or looseness is liable to be produced, is reduced, thereby enabling a noiseless smooth operation. Especially, the first and second operating members are carried on the rotary shafts rather than on stationary shafts as in the prior art and hence, a sliding resistance cannot be produced between the first operating member and the driving rotary shaft or between the second operating member and the follower rotary shaft, because they are rotated in unison with each other. In addition, the driving rotary shaft itself which is an output shaft of the electromagnetic drive source also serves to support the first operating member and hence, the number of parts and the number of assembling steps are further reduced. Moreover, the driving rotary shaft, the follower rotary shaft, the first and second operating members and the operatively connecting means can be assembled to the housing of the electromagnetic driving source to form an assembly and hence, the assemblability and the handling of the rotary electromagnetic actuator are enhanced remarkably.
To achieve the above object, according to a second aspect and feature of the present invention, there is provided a rotary electromagnetic actuator comprising an electromagnetic driving source including a driving rotary shaft rotatably carried in a housing and driven in rotation by an electromagnetic force, a follower rotary shaft rotatably carried in the housing, a first operating member carried on and rotated in unison with the driving rotary shaft, a second operating member carried on and rotated in unison with the follower rotary shaft, and an operatively connecting means for permitting the first operating member and the second operating member to be rotated in association with each other without through a slide area, wherein no lubricant is applied between the driving rotary shaft and the first operating member, between the follower rotary shaft and the second operating member, or to the operatively connecting means.
With the above arrangement, when the electromagnetic driving source is driven to rotate the driving rotary shaft, the first operating member is rotated in unison with the driving rotary shaft. This rotation of the first operating member is transmitted through the operatively connecting means to the second operating member to rotate the second operating member in unison with the follower rotary shaft. Therefore, the first and second operating members can be rotated in unison with each other. In addition, it is unnecessary to provide a pin and an elongated bore, or means for converting a rectilinear motion to a rotational motion such as a stationary shaft and a link in a path of transmitting the driving force from the electromagnetic driving source to the first and second operating members. Therefore, not only the number of parts and the number of assembling steps are reduced, but also the number of slide areas where a friction resistance or looseness is liable to be produced, is reduced, thereby enabling a noiseless smooth operation. Especially, the first and second operating members are carried on the rotary shafts rather than on stationary shafts as in the prior art and hence, a sliding resistance cannot be produced between the first operating member and the driving rotary shaft and between the second operating member and the follower rotary shaft, because they are rotated in unison with each other. In addition, the driving rotary shaft itself which is an output shaft of the electromagnetic driving source also serves to support the first operating member and hence, the number of parts and the number of assembling steps are further reduced. Moreover, the driving rotary shaft, the follower rotary shaft, the first and second operating members and the operatively connecting means can be assembled to the housing of the electromagnetic driving source to form an assembly and hence, the assemblability and the handling of the rotary electromagnetic actuator are enhanced remarkably. Especially, there is no slide area between the driving rotary shaft and the first operating member and between the follower rotary shaft and the second operating member as well as in the operatively connecting means, and hence, it is unnecessary to apply a lubricant such as silicone grease, and an increase or decrease in sliding resistance due to a variation in viscosity of the lubricant is not produced. As a result, it is unnecessary to provide an electromagnetic driving source having a large capacity required to overcome a large sliding resistance. This can contribute to a reduction in size of the rotary electromagnetic actuator and also eliminate a disadvantage that when the sliding resistance is small, the driving force of the electromagnetic driving source becomes excessive, resulting in the generation of a noise at the end of a stroke.
To achieve the above object, according to a third aspect and feature of the present invention, there is provided a rotary electromagnetic actuator comprising a rotary solenoid including a driving rotary shaft rotatably carried in a housing and driven in rotation by an electromagnetic force, a follower rotary shaft rotatably carried in the housing, a first operating member carried on and rotated in unison with the driving rotary shaft, a second operating member carried on and rotated in unison with the follower rotary shaft, and an operatively connecting means for permitting the first operating member and the second operating member to be rotated in association with each other.
With the above arrangement, when the rotary solenoid is driven to rotate the driving rotary shaft, the first operating member is rotated in unison with the driving rotary shaft. This rotation of the first operating member is transmitted through the operatively connecting means to the second operating member to rotate the second operating member in unison with the follower rotary shaft. Therefore, the first and second operating members can be rotated in unison with each other. In addition, it is unnecessary to provide a pin and an elongated bore, or means for converting a rectilinear motion to a rotational motion such as a stationary shaft and a link in a path of transmitting the driving force from the electromagnetic driving source to the first and second operating members. Therefore, not only the number of parts and the number of assembling steps are reduced, but also the number of slide areas where a friction resistance or looseness is liable to be produced, is reduced, thereby enabling a noiseless smooth operation. Especially, the first and second operating members are carried on the rotary shafts rather than on stationary shafts as in the prior art and hence, a sliding resistance cannot be produced between the first operating member and the driving rotary shaft or between the second operating member and the follower rotary shaft, because they are rotated in unison with each other. In addition, the driving rotary shaft itself which is an output shaft of the electromagnetic driving source also serves to support the first operating member and hence, the number of parts and the number of assembling steps are further reduced. Moreover, the driving rotary shaft, the follower rotary shaft, the first and second operating members and the operatively connecting means can be assembled to the housing of the rotary solenoid to form an assembly and hence, the assemblability and the handling of the actuator are enhanced remarkably. Especially, the use of the rotary solenoid as an electromagnetic driving source ensures that the variation in driving force with respect to the angle of rotation of the driving rotary shaft is decreased, thereby eliminating such a disadvantage that the driving force of the rotary solenoid becomes excessive, causing the generation of a noise at the end of a stroke.
To achieve the above object, according to a fourth aspect and feature of the present invention, there is provided a rotary electromagnetic actuator comprising an electromagnetic driving source including a driving rotary shaft rotatably carried in a housing and driven in rotation by an electromagnetic force, a follower rotary shaft rotatably carried in the housing, a first operating member carried on and rotated in unison with the driving rotary shaft, a second operating member carried on and rotated in unison with the follower rotary shaft, and an operatively connecting means for permitting the first operating member and the second operating member to be rotated in association with each other, the first and second operating member being provided at their free ends respectively with locking surfaces capable of inhibiting the movement of a select lever for an automatic transmission, the locking surfaces of the first and second operating members being arranged, so that they face a path of movement of the select lever in a non-excited state of the electromagnetic driving source to inhibit the movement of the select lever from a parking range and a neutral range, and they are retracted from the path of movement of the select lever upon excitation of the electromagnetic drive source to permit the movement of the select lever from the parking range and the neutral range.
With the above arrangement, when the electromagnetic driving source is driven to rotate the driving rotary shaft, the first operating member is rotated in unison with the driving rotary shaft. This rotation of the first operating member is transmitted through the operatively connecting means to the second operating member to rotate the second operating member in unison with the follower rotary shaft. Therefore, the first and second operating members can be rotated in unison with each other. In addition, it is unnecessary to provide a pin and an elongated bore, or means for converting a rectilinear motion to a rotational motion such as a stationary shaft and a link in a path of transmitting the driving force from the electromagnetic driving source to the first and second operating members. Therefore, not only the number of parts and the number of assembling steps are reduced, but also the number of slide areas where a friction resistance or looseness is liable to be produced, is reduced, thereby enabling a noiseless smooth operation. Especially, the first and second operating members are carried on the rotary shafts rather than on stationary shafts as in the prior art and hence, a sliding resistance cannot be produced between the first operating member and the driving rotary shaft or between the second operating member and the follower rotary shaft, because they are rotated in unison with each other. In addition, the driving rotary shaft itself which is an output shaft of the electromagnetic driving source also serves to support the first operating member and hence, the number of parts and the number of assembling steps are further reduced. Moreover, the driving rotary shaft, the follower rotary shaft, the first and second operating members and the operatively connecting means can be assembled to the housing of the electromagnetic driving source to form an assembly and hence, the assemblability and the handling of the rotary electromagnetic actuator are enhanced remarkably. Especially, since the locking surfaces capable of inhibiting the movement of the select lever for the automatic transmission from the parking range or the neutral range are provided at the free ends of the first and second operating members, respectively, the select lever can be previously prevented from being inadvertently operated from the parking range and the neutral range.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.